Nitro ($149, $299 bundled with PSP 42 and PSP 84), a new multimode filter and multi-effects processor from PSPaudioware, is the latest in the company's

Nitro ($149, $299 bundled with PSP 42 and PSP 84), a new multimode filter and multi-effects processor from PSPaudioware, is the latest in the company's superb line of plug-ins. Like PSP's Vintage Warmer multiband compressor-limiter and the PSP 42 and PSP 84 Lexicon delay-line emulations, Nitro combines a realistic hardwarelike GUI with loads of under-the-hood parameters for more serious tweaking.

The plug-in is available in VST format for Mac and PC, DirectX format for PC, and Audio Units (AU) format for Mac.

Smooth Operators

Nitro is a 4-stage processor, and each stage can use any of 17 effects processes, or Operators. The signal path is freely configurable, allowing the stages to be arranged in any order. Eleven predefined paths are provided to get you started. Stages can also be turned off to save CPU power.

The Operators fall into two broad categories: filters and other effects. The filters include lowpass, bandpass, and highpass versions in three styles: state-variable (SVF), biquad (BQ), and Moog. The first two — typical of vintage synths — are 2-pole (12 dB per octave rolloff) with resonance, and SVF filters that can self-oscillate. The BQ category also includes a band-reject (notch) filter. The Moog filters are 4-pole and also capable of self-oscillation.

Other effects include Comb, a comb-filter; Phaser, a phase shifter, Lo-Fi, a downsampler and bitcrusher; SAT, a waveshaping-based saturation algorithm; Wid/Bal, a stereo width and balance effect; Panner, a panning effect that gives you independent control of the left and right channels; and Glide, a stereo delay line with separate delay controls for each channel. There are no startlingly new effects here — it's the configurability of the signal path together with extensive modulation options that make Nitro explosive.

The Face of Nitro

Each Nitro operator has its own control panel with knobs for the chosen effect's two most important settings. There are also On, Solo, and Mid-Side buttons, and an output-level slider. Once you've set up a configuration or loaded a preset, you can do most tweaking with those controls.

If you want to get deeper into programming, most of the action takes place in Nitro's central LCD display, which is divided into eight pages: CFG (configuration), OP (Operators), LFO, ENV (envelope follower), ADS (ADSR envelope), MOD (modulation routing), LIB (preset and bank management), and GLB (global settings).

The MOD page allows you to route either of Nitro's two LFOs, the envelope follower, the ADSR envelope, and any incoming MIDI message to any of the Operator settings, any modulator setting, and amazingly, to any of the signal levels on the CFG page. That allows you, for example, to do a kind of ducking by using the envelope follower to lower the output level of one operator based on the output level of another, as in factory presets A-53 and A-56.

Configure It Out

The CFG page is the most complex and arguably the most important. It presents you with a matrix of 26 boxes. The top-left box represents Nitro's input, the bottom-right box the output, and the boxes on the diagonal represent the four Operators. Connections are made by click-dragging in one of the boxes to set the level of the signal routed from the Operator above or below the box to the Operator to the left or right of the box. (In the case of the left column, the signal source is Nitro's input, and in the case of the bottom row, the destination is Nitro's output.) That may sound complicated, but it takes only a few seconds of use to grasp fully.

Because there are no restrictions, you can create feedback loops, even directly back into an operator. The LCD contains a flashing feedback-warning indicator. Feedback can be useful in some configurations, for example to add feedback to the stereo-delay effect, Glide, such as in factory presets A-20 and A-53.

Nitro comes loaded with 192 factory presets, organized into 3 banks of 64. The LIB page provides complete preset and bank management, allowing you to load and save individual presets or entire banks. The factory presets range from typical filtering and delay effects to those that take advantage of Nitro's modulation and configuration routings. For an example of what Nitro can do, listen to the audio clip (see Web Clip 1) posted for this review at

If you enjoy reaching for the unusual in effects processing and don't mind getting your hands dirty, Nitro is a plug-in you should check out. You can download a feature-limited demo from the PSP Web site.

Overall EM Rating (1 through 5): 4PSPaudioware
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